Punch



April s 1924.A 1,48%@

' J. F. DOOLITTLE PUNCH Filed Nov. 1 I 1920 Erl' n jfl?.

Patented Apr. 8, 1924.

STATS.

JOHNl r. noonrrTLE, 'or Ennrunnrns TEXAS, Assionon 'rorEE CLEvELANDs'rEELi troon COMPANY, OE CLEVELAND, OHIO, A CORPORATION ory oEro.

PUNCH.

Application led November 1, 1920. Serial No. 421,131.

To all 'whom t may concern:

Be it known that I, JOHN F. DooLrr'rLE, a citizen of the United States, residing at Falfurrias, in the county of Brooks and State of Texas, have invented certain new and useful mprovements in Punches, of which the following is a specification.

This invention relates to punches, and is a continuation in part of my co-pending application, Serial No. 349,631, filed January 5, 1920, for punch, which application was allowed July 21, 1920, and has become Patent No. 1,368,327, granted February 15, 1921.

The object of the invention is to provide an improved construction for firmly securing a punching or similar tool to the reciprocating shaft, and which arrangement provides relatively large bearing surfaces between the punching tool and its securing member, so as to reduce the liability of breakage of the tool; which also insures accurate centering of the tool relative to the work; and which enables several tools of dierent sizes to be securely clamped to the same operating shaft with certainty of accurate centerinof all of such tools.

urther objects of the invention are in part obvious and in part will appear more in detail hereinafter.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the drawings Fig. 1 represents a sectional elevation of one form of the invention; Fig. 2 is a similar view, illustrating a different size of tool and clamping nut; and Fig. 3 is a plan view of a clamping nut.

1 illustrates the reciprocating shaft of the punching machine to which is secured the punching tool. Said shaft is threaded at 2 to receive the threads of the coupling nut 3 which is screwed upon the shaft for securing thereto the punch L1. In the drawings the punch is illustrated as provided with an operating end 5 for punching holes, but it will of course be understood that the tool may have an operating end portion for setting rivets or performing other operations than punching holes.

The end of the shaft 1 is cut o square to form an abutment 6 which contacts the end surface of the punch 4. Said punch is clamped against the abutment 6 by the coupling nut and the parts are so arranged as to enable a series of punches of dierent sizes to be secured tothe same shaft. Preferably the arrangement is such that several punches, according to size, may be made from bar stock of different sizes so as to reduce the cost for tool steel. This result is secured by providing coupling nuts of different sizes.

The inner surfaces of the several coupling nuts which receive the tools are alike in form but different in diameter. These surfaces, indicated at 9, are frusto-conical and preferably slope uniformly throughout at an angle of approximately 12 to the axis of the nut. Each nut is adapted to receive a single tapered body, the frusto-conical head 10 being tapered to correspond with the co-operating face of the nut. .This relatively long conical surface avoids abrupt shoulders and distributes the strains over some length of the tool and avoids breakage or snapping of the head of the tool from its body portion.

Thus I have devised a punch in which ef fective frictional engagement is secured between the clamping nut and punch member without danger of the parts jamming or freezing; and in which proper centering of the punch with respect to the work is assured. Wear between the parts is reduced to a minimum by the uniform degree of engagement throughout the entire zone of engagement and danger of accidental loosening of the punch from its seat is precluded. Thus a high degree of eciency is attained and the life of the tool prolonged.

What I claim is: n

1. In combination, a plunger, a coupling nut detachably secured thereto and provided with an unbroken frusto-conical seat therein, and a punch having an unbroken frustoconical surface engaging directly the seat of said coupling nut, the taper of said engaging surfaces having the same angle of inclination toward the cutting end of the punch and being uniform throughout.

2. Tn combination, a plunger, a coupling nut detachably secured thereto and provided with an unbroken frusto-conical seat therein, the inclination of said seat being uniform throughout and making an angle of approximately twelve degrees with the axis of said coupling nut, and a punch having an unbroken frusto-conical Surface engaging directly the seat of said coupling nut, the angle of inclination of the engaging surface of the punch corresponding to that of said seat and the taper of said surfaces being in a direction toward the cutting end of the punch. y 10 In. testimony whereof I hereby aHiX my signature.

JOHN F. DOOLITTLE. 

